Safety-crank for internal-combustion motors.



J. D. POLLOCK.

SAFETY CRANK FOR INTERNAL COMBUSTION MOTORS. APPLICATION FILED MAR. z, 1916.

LQOKWEM Patented Dec. 12,1916.

JESSE 1). POLLOCK, OF CARPENTER, VTYOMING.

SAFETY-CRANK FOR INTERNAL-COMBUSTION MOTORS.

Specification of Letters Patent.

Patented Dec. 12, 1916.

Application filed March 7, 1916. Serial No. 82,618.

To all whom it may concern Be it known that I, Jnssn D. POLLOCK, a citizen of the United States of America, and resident of Carpenter, in the county of Laramie and State of Wyoming, have invented certain new and useful Improvements in Safety-Cranks for Internal-Combustion Motors, of which the following is a specification.

This invention relates to internal combustion motors and particularly to means for cranking said motors.

An object of this invention is to produce a safety engine cranker or starter in which the coupling mechanism is released upon back firing of the motor, thereby automatically insuring against accident and the danger incident to this operation.

A further object of this invention is to produce a device of this character which is positive in its operation and of such simple construction as to be readily applied to automobiles now in common use.

With the foregoing and other objects in view, the invention consists in the details of construction, and in the arrangement and combination of parts to behereinafter more fully set forth and claimed.

In describing the invention in detail, ref erence will be had to the accompanying drawings forming part of this specification in which like characters denote corresponding parts in the several views, and in which Figure 1 illustrates a view in elevation of a fragment of the front of an automobile with the invention applied thereto; Fig. 2-

illustrates a top plan view thereof, the easing of the mechanism being in section; Fig. 3 illustrates a sectional view on the line 3-3 of Fig. 2; and Fig. 4 illustrates an enlarged detail view of part of the mechanism.

In these drawings 5 denotes the crank shaft of an explosive motor, 6 a stub shaft having a recess 7 in its end for the reception of an end of the crank shaft, and 8 illustrates a set screw for coupling the shaft and stub shaft together, although a ratchet connection may here be substituted.

A lever or crank 9 is mounted on the shank 10 of a set screw 11, the said screw being threaded in the end of the stub shaft, as shown in Fig. 3. The crank 9 has a handle 13 and the said handle extends through a dog 14, said dog having a nose 15 which engages the te th of the r t et he l 7, which ratchet wheel is preferably formed integral with the stub shaft (3. An apertured disk or plate 17 fits on the shaft 6 and the shaft rotates independently of it. Furthermore, the disk has arms 18 to which pawls 19 are pivoted, the said pawls being under the in fluence of springs 20, which springs serve to hold the pawls in engagement with the teeth 21 of a ratchet wheel 22, which ratchet wheel is mounted on the shaft 6. The ratchet wheel 22 has an arm 23 from which a pin 24 extends, the said pin lying in a slot 25 of the dog 14. The purpose of this arrangement is to effect a disengagement of the dog from the ratchet wheel 17 should there be a back fire in the motor. hen the crank is rotated, the dog engages the teeth of the ratchet wheel 17 thus communicating m0- tion to the crank shaft of the motor. On the clockwise movement of the crank shaft, the dog travels a slight distance, that is to say a distance equal to the length of the slot 25 before the pin 24 strikes the wall of the outer end of the slot and when this occurs, the ratchet wheel 22 is rotated in a clockwise direction so long as the parts are normally operated. Should there be a back fire however, the dogs 19 would engage the ratchet wheel 22 and arrest the movement of said ratchet wheel since the said ratchet wheel is loose on the stub shaft 6. When the ratchet wheel 22 comes to rest, the dog would of course move longitudinally on the pin 24 and as the pin is in a diagonal slot of the dog, the action of the pin would be to disengage the nose of the dog from the ratchet wheel 17, thus freeing the said ratchet wheel to permit the motor to. run backward without further communicating motion to the crank shaft.

The plate 17 is held stationary by means of a rod 27 which extends from one of the arms 18 to a staple or other anchorage 28. Furthermore, a spring 29 is connected to the arm 23 and to the pawl so that the said pawl is held normally out of engagement with the ratchet wheel thereby.

I claim 1. In a safety motor crank, a shaft, a ratchet wheel thereon, a dog adapted to engage the ratchet wheel, means for supporting the dog whereby it may rotate the shaft in one direction, a ratchet wheel rotatable on the said shaft, an arm thereon having a pin, said dog having a cam slot to receive the pin, the said dog being slidable with re lation to the pin, means for holding the dog normally out of engagement With the ratchet Wheel, and a stationary member having dogs for engaging'the second mentioned ratchet wheel to prevent anti-clockwise movement thereof npon back fire of the motor.

2. In a safety motor crank, a crank shaft having a ratchet wheel thereon, a dog for engaging said ratchet Wheel, said dog having a cam slot, a ratchet wheel rotatable on the said shaft and having a pin extending through the said cam slot, and means for preventing anti-clockwise motion of the sec ond mentioned ratchet Wheel.

3. In a safety motor crank, a crank shaft, a ratchet Wheel thereon, an arm rotatable with relation to the shaft, a dog connected to the said arm and moving therewith, said dog having a slot in its inner end, a ratchet wheel rotatable on the shaft, a pin projecting from said ratchet wheel into the slot of the dog, a plate on the said shaft, said plate having arms, pawls pivoted on said arms and adapted to engage the second mentioned ratchet wheel to prevent anti-clockwise rotation of the said ratchet Wheel, and means for holding the dog normally out of engagement with the ratchet wheel.

In testimony whereof, I affix my signature in the presence of two witnesses.

JESSE D. POLLOCK.

l/Vitnesses:

SYLvns'rnn H. SIBLEY, HENRY B. CoLBURN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

